Low levels of flavonoids in Arabidopsis thaliana during phenanthrene exposure suggest new roles for a flavanone 3-hydroxylase
Bibliographic record
Abstract
Polycyclic aromatic hydrocarbons (PAHs) contamination impacts the well-being of fauna, flora, and the environment. PAHs are a group of compounds consisting of two or more benzene rings. Due to their structure, PAHs are very stable, generally non-reactive and resistant to biodegradation; yet these compounds are cytotoxic in biological systems. In plants, PAHs induce oxidative stress and cell death, and inhibit growth. Previous PAH exposure studies from our laboratory showed an up-regulation of the Arabidopsis thaliana gene At3g51240. At3g51240 encodes a flavanone 3-hydroxylase (F3H), an enzyme catalyzing the hydroxylation of flavanones, key intermediates in the flavonoid biosynthesis pathway. Considering that flavonoids may act as antioxidants and protect cells against oxidative stress, we hypothesized that F3H was important in alleviating PAH-induced stress symptoms. Analysis of flavonoid content by high performance liquid chromatography showed low levels of flavonoids in phenanthrene-treated plants. Analysis of At3g51240 loss-of-function mutant plant lines growing on phenanthrene-containing growth media showed reduced phenotypic stress responses. Interestingly, low levels of H2O2 were observed in the mutant plants, suggesting that this putative flavanone 3-hydroxylase may be involved in PAH oxidation, with the consequent H2O2 generation. Furthermore, in vitro assays with purified recombinant 6xHis tagged AT3G51240 showed enzyme activity on the PAH when phenanthrene was used as a substrate. Together, these data suggest that F3H is involved in PAH detoxification in planta with the subsequent accumulation of toxic metabolites. This research also indicates the potentiality of using specialized metabolism enzymes such as oxidoreductase in the genetic engineering of plants to remediate PAH-contaminated soils.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".